Optical transmission systems constitute the basic carrier for most telecommunication systems. Many optical transmission technologies are based on the principle of wavelength division multiplexing (WDM) or Dense WDM (DWDM), where the transmission channels are carried by optical signals over different wavelengths or different bands of wavelengths. In some WDM or DWDM systems, it is desirable to use a colorless add architecture that can be combined with a plurality of similar or identical laser transmitters to provide a plurality of different wavelength channels. The colorless add architecture may comprise a plurality of filters that have different band-pass spectra that select different wavelength bands from the same or similar laser transmitters to provide the different wavelength channels. The colorless add architecture may be advantageous since one type of laser transmitters may be needed to provide all the wavelength channels, which may reduce inventory requirements and total cost of the system.